BACKGROUND: Almost all published work on chronic fatigue syndrome
(CFS) has involved retrospective surveys of cases, which may
introduce recall bias. Only medical records collected before
diagnosis of CFS can eliminate this.
METHODS: Using data
collected several years prior to the development of the
illness, we performed a case control study, comparing the
reported illness records of all people who subsequently made
an insurance claim as a result of CFS, with those of future
multiple sclerosis (MS) claimants, and those of non-claimant
RESULTS: The study encompassed 133 CFS, 75 MS
and 162 NC cases. CFS cases had recorded significantly more
illnesses at time of proposal for insurance than the two
control groups, and had significantly more claims between
proposal and diagnosis of their disorder. Almost all disease
categories were reported higher in future CFS sufferers,
lethargy having the highest odds ratio after adjustment in a
INTERPRETATION: The results of this paper
on CFS patients who claim permanent health insurance do not
support a specific viral or immunological explanation for CFS.
We conclude that abnormal illness behaviour is of greater
importance than previously recognised.